What's the deal with @?

Probably a stupid question, but i'm fairly new to PHP and I've seen people call (especially mySQL) functions with @ in front of them, although most scripts I've seen don't. Is there anything special about using @ to call functions?

Thanks

Using @ will suppress an error from being output if there is one.

It's used a lot with mysql as you said so a "Could not connect to db XXXX" message is not spit out.

continuing on with that MastaM00 said,

you also can use @ on variables, etc just about everthing in php you can place a @ in front of, except for if, while, for, ....

I use them sometimes if im programming, if i know there is a possiblity that something is not going to work, i will place a @ in front of the function.

Continuing on with that

It's also used if you want to create your own customized error messages:

@mysql_query($query) or die("Customized Error Message");